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From: chris@mimsy.UUCP
Newsgroups: comp.lang.c
Subject: Re: structure enhancements
Message-ID: <9143@mimsy.UUCP>
Date: Wed, 28-Oct-87 09:35:25 EST
Article-I.D.: mimsy.9143
Posted: Wed Oct 28 09:35:25 1987
Date-Received: Sat, 31-Oct-87 04:41:48 EST
References: <444@root44.co.uk> <165600018@uiucdcsb>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 30

In article <165600018@uiucdcsb> mccaugh@uiucdcsb.cs.uiuc.edu writes,
in reply to the idea that since

	a += n;

means, effectively,

	a = a + n;

that

	p ->= member;

ought (effectively) to mean

	p = p -> member;

>... according to Harbison & Steele, page 149: "The value (of an
>indirect component selection expression) is the named member of the
>union or structure and (so) is an LVALUE." But on page 184 appears
>the warning that "the result of an assignment expression is NEVER
>an lvalue." ... Thus p -> n  must be an lvalue ("namely", n) while
>p ->= n cannot be.

True, but irrelevant.  The result of `a += n' is also not an lvalue.
The only relevance that `lvalue-ness' has with op= operators is that
the left hand side of the op= operator must be an lvalue.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris